Silos are well known agricultural buildings for storing and conditioning fodder or forage in bulk form until it is to be used for animal feed. The silage is typically loaded into the silo by depositing it within the silo from the top. The silage is then unloaded from a working face at the top of the bulk silage, conveyed outside the silo through a vertical opening in the silo wall, and discharged via a vertically disposed chute running down the outside of the silo.
An alternate method of conveying silage from the top of the stack has been to unload it through a vertical chute or passage formed in the silage itself along the inside of the silo wall. Apparatus and a method for forming such an inside discharge chute are disclosed in my U.S. Pat. Nos. 3,063,497, issued Nov. 13, 1962; 3,063,585, issued Nov. 13, 1962; and 3,961,693, issued June 8, 1976. As shown in those patents, such a chute can be formed by positioning a form or torpedo adjacent the inside wall of the silo and lifting the torpedo as the silo is filled to leave a chute in the path of the torpedo. Such chutes are not ideal because they can sometimes collapse or become jammed. Alternately, such a chute can be formed by erecting a vertical series of inwardly bowed doors along the inside wall of the silo adjacent to the discharge opening before the silo is filled. After the silo is filled, the doors level with the working face of the silage are progressively removed to expose the chute as the silo is unloaded. The successive doors of the system must be custom fit to an individual silo construction, and loose hardware needed to assemble and disassemble the chute forming means can become lost or be dropped when doors are assembled or disassembled by a person standing within the conventional discharge chute outside the silo wall.